Choudhury Snehashis, Li Gaojin, Singh Rohit R, Warren Alexander, Liu Xiaotun, Archer Lynden A
School of Chemical and Biomolecular Engineering, Cornell University, Ithaca, New York 14853, United States.
Langmuir. 2020 Aug 11;36(31):9047-9053. doi: 10.1021/acs.langmuir.0c00577. Epub 2020 Jul 30.
When ion transport in a binary liquid electrolyte is driven at potentials above the thermal voltage, an extended space charge region forms at the electrolyte/electrode interface and triggers the hydrodynamic instability termed electroconvection. We experimentally show that this instability can be completely arrested in soft colloidal suspension electrolytes composed of low concentrations of polymer-grafted nanoparticles in a liquid host. The mechanism is revealed by means of X-ray scattering, Brownian dynamics calculations, and linear stability analysis to involve overlap of the soft particles at low particle fractions to create a jammed, nanoporous medium that resists convective flow by a Darcy-Brinkman like drag on the electrolyte solvent.
当二元液体电解质中的离子传输在高于热电压的电位下被驱动时，在电解质/电极界面会形成一个扩展的空间电荷区域，并引发被称为电对流的流体动力学不稳定性。我们通过实验表明，在由低浓度聚合物接枝纳米颗粒在液体主体中组成的软胶体悬浮电解质中，这种不稳定性可以完全被抑制。通过X射线散射、布朗动力学计算和线性稳定性分析揭示了其机制，即在低颗粒分数下软颗粒的重叠形成了一种堵塞的纳米多孔介质，该介质通过类似达西 - 布林克曼的对电解质溶剂的阻力来抵抗对流流动。
